1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to processing digital content, and more particularly, to preventing unauthorized use of digital content.
2. Description of the Related Art
Recently, a technique of receiving and storing broadcast contents, and various personal video recording/digital video recording (PVR/DVR) systems for supporting the technique have been developed.
Once content that contains copy control information is stored in a device, the content may be prevented from being copied to another device or via a digital interface. That is, if the content, whose copy control information represents “copy once” indicating that copying is permitted only once, is stored in a storage device, the copy control information is changed to represent “copy no more” indicating that further copying is not permitted. Thus, the content cannot be copied to other storage devices but can be moved. Hereinafter, “moving” means that the content is removed from the original storage device in which the content was originally stored when the content is copied to another storage device. Thus, when the content is moved to another storage device, reproduction of the content in the other storage devices including the original storage device is not allowed.
However, even if the content is moved from the original storage device, it is possible to reproduce the content by copying the content of the original storage device on a bit-by-bit basis in order to back up content of the original storage device and then reproducing the content by using the backed up content. Thus, the content can be distributed without permission. Such an attack is referred to as a “disk cloning attack”.
Accordingly, when content, which is not permitted to be copied, is moved from a storage device to a new storage device, a new content management mechanism guaranteeing that the content cannot be reproduced in other storage devices except the new storage device is needed.